Operating Problems of Lubrication of Friction Nodes in Mining Machines Working in an Aggressive Environment

Abstract

The paper presents problems related to the lubrication of moving machine nodes that are operating in an aggressive environment occurring in copper mines. The analysis was based on the exploitation of self-propelled wheeled machines, such as transport vehicles, loaders, drilling and anchoring cars. In self-propelled machines there are from 15 to 40 moving parts exposed to high impact loads and stresses. These are mainly bolted joints performing swinging motion as well as rotary motion at low rotational speeds up to 10 rpm. Observations and operational tests of several dozen manifolds and pumps operating in the environment occurring in KGHM Polska Miedź copper mines were carried out during two years. It was stated that elements made of aluminum or its alloys should not be used, and should be replaced with bronze (the proposal results in the increase of weight and costs of the system, but observational studies have shown that the durability and reliability of pumps increased more than three times, and the durability of the manifolds with the bronze body has increased more than five times). It was recommended to avoid the use of electronic systems on actuators in central lubrication systems (control systems should be encapsulated) and to use pumps with a hydraulic drive, which is commonly used in the working elements of machines used in a copper mine. The proposed lubrication system made of bronze and with hydraulic drive is several times more durable and cheaper to operate compared to the central lubrication systems used so far.